Vehicle spring manufacturing method



Aug- '15 1950 H. B. cLARY 2,518,867

vEHIcLE SPRING MANUFACTURING METHOD Filed April 15, 194e 2 sheets-sheet 1 INVENToR. Har/g 5. C/a/g FiF- El;

14 TTORNE V5 Aug. l5, 1950 H. B. CLARY 2,518,867

VEHICLE SPRING MANUFACTURING METHOD.

2 ySheets-Sheet 2 Filed April 1s, 1948 FJ'. [E h INVENTOR. Harry C/ar'g way/e HT TORNE YS Patented Aug. l5., 1^95 VEHICLE SPRING MANUFACTURING METHOD Harry B. Clary, Oakland, Calif., assignor to Lahcr ySpring and Tire Corporationakland, Calif., a corporation of Oregon Application April 13, 1948, Serial No. 20,758

4 claims. (el. 25a- 173) This invention relates generally to methods for the manufacture of vehicle springs of the semielliptical leaf type.

The conventional method for the manufacture of vehicle springs of the elliptical leaf type is to separately handle and process each leaf of the spring assembly, throughout the successive heating, bending and hardening operations. For the bending operation each leaf must be bent by the use of special pattern strips or forms, and the forms for each leaf must be different. Leaves manufactured in this fashion must be carefully sorted and checked for each assembly, and frequently some cold bending is required for the final assembly. In making the final assembly it is difficult to maintain accurate alignment of the shackle bolt eyes which are customarily formed in the ends of the main leaf, thus further complicating the sorting and selection of the leaves for each final assembly. Such individual handling and processing operations materially add to the cost of the final spring, and require a relatively high degree of skill on the part of the workmen, both in the processing and final assembly operations.

It is a general object of the present invention to provide a method for the manufacture of vehicle springs which will avoid the individual handling and processing of the leaves as described above. The present method is characterized by the handling and processing of all of the leaves of a spring assembly as a unit, including the heating, bending and hardening operations' whereby in one general operation, which is no more diilicult or time consuming than the processing of an individual leaf, all of the leaves of a complete spring assembly are completed.

'Further objects of the invention include the elimination of separate forms or pattern strips for each leaf, facilitating proper alignment of the shackle bolt eyes in the final assembly, eliminating troublesome selection and sorting of individual leaves, facilitating making spot tests on production, and providing a spring manufacturing method which can be readily mastered by ordinary Workmen without a long training period.

Additional objects of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing- Figure 1 is a side elevational view showing an assembly of spring leaves prior toprocessing, and showing Y the majority, of `the ,secondary leaves assembled upon that side of the main leaf, opposite from the side which the secondary leaves normally koccupy in the completed spring.

Figure 2 is a plan view showing the assembly of Figure 1 in a bending machine for bending all of the leaves in one operation.

Figure 3 is an end view of the bending chine illustrated in Figure 2.

Figure 4k is a view like Figure 1, but showing kthe assembly after the bending operation.

Figure 5 is a view like Figure l, but showing how the leaves after being processed in one assembly, are yreassembled with the secondary leaves upon the convex side of the main leaf.

Figure y6 is a view like Figure 5, but showing all of the leaves held in close relationship by the center tie-bolt.

As previously stated it is conventional practice in the manufacture of vehicle springs of the semi-elliptical leaf type to separately process the diierent leaves, and then to assemble leaves of proper curvature to form the final spring. The present invention departs from such conventional practice in that after cutting the separate leaves from suitable steel stock, and. forming eyes in the ends of the main leaf, the leaves are `all loosely assembled with all or a majority of the secondary leaves disposed in the order of their length upon that side of the main leaf which subsequently becomes the convex side. While so assembled the leavesr are heated and bent in one operation, after which they are hardened.

In Figure 1, I have shown the leaves of a spring looselyassembled in the manner described above. The main leaf I0 is formed with the end eyes I I, and all of the leaves are centrally drilled to receive the retaining bolt I2. The secondaryk leaves are numbered I3 to I8 inclusive. The leaves I4 to I8 inclusive are assembled in the order of their length upon the lower side of the main spring ID, Because the leaf I3 is too long to be accommodated between the eyes II, it is placed upon the upper side of the main leaf IB.

All of the secondary leaves are of slightly lesser thickness than ythe main leaf I0.

compared to 1A, inch for the secondary leaves.

The entire assembly of Figure l is placed in a suitable heating furnace and heated to a proper .temperature for hot bending. It is then placed in a suitable bending machine such as is illus-` trated in Figure 2, and which is adapted to bend all of the leaves in one bending operation. This machine consists of a work table 2I provided with parallel stationary and movable beams. 22

For example vl"the main leaf may be inch in thickness as assembly designated generally by number 58 is* adapted to rest upon a suitable surface suchas provided by the side-by-side beams 59.

With suitable adjustment of the various thrust rods, it is evident that when' the beam 23' is retracted the spring assembly can'` be' deposited upon the I beams 59, and thereafter beam 23 can be advanced to bend the entire: assembly tof the desired shape, as illustrated in Figure 2. In conjunction with this bending operation` it is desirable to provide a set of inner and outer pattern strips or forms B-I andI 6'2. These'pattern-- strips have a' general curvature corresponding tothat to which the complete" assembly is bent; and they are provided with central openings (i3I and 64 adequate to pass the ends of the retaining bolt I2. One set of forms' serves for the entireassembly, thus obviating forms: for all of the individual leaves as'requlred in the past.

When the beam'A 23 is' retracted following a hot bending operation all of theleavesfstraighten out aV certainl amount, but the mainlea'ff Il) springs back a greater amount than` the se'c-v ondary leaves, dueI to the' fact that it ismade of thicker stock. In' atypical lnstan'ce'theleaves immediately after the'bending operation will` ap pear as shown in Figure-4'. The main'- leaf Ifhas' the least curvature or arch of all o'f the-leaves; The secondary leaf I3;has'considerably morearch than the main leaf Il); but slightly' less' than the leaf I4. Leaf I5 hasslightly more'arclr than' the' leaf I4 and leaf I64 slightly' more arch than' leaf I5. The leaves I6, I'I andI` |58 have substantially the same arch.

It may be explained' at' thispo'int' that in 4many instances all ofthe secondary leaves can be as`' sembled on one side of the' main leaf for' the bending and subsequent processing operations: Where it is necessary', because of its length, to place the leaf I'3 on the uppersdeof'theassembly' (Figure 1), then it is generally' necessary to bend the assembly to a slightly greater arch thanI would otherwise be the' case:

The assembly is now subjected-` to suitable treatment for hardening the' leaves, and" which'- can be carried out by conventional methods iff-'- volving for examplethe'reheating oftheassembl'y' followed by its immersion in' oil' or like liquid to chill the same.

After the hardening operation, the retaining bolt I2 is removed, and the various leaves reassembled in the order illustrated in Figure 5'-, As'- suming that leaf I3 has been' bent on the outside, then the arch of theA mairrleaf In* is'checked' before final assembly, and' any arch' in excess' of the proper amount is removed by cold bending. In the assembly of Figure 5Y it will* b'e noted that' the-leaf I3 has anarch' considerably greater than' the main leaf IG, and the arch for each' of the leaves I4, I5 and IS is progressively greater. K The' springs can now be clamped' together by tighten' ing the tie-bolt 91, toform the final assembly of Figure 6. All of the leaves are nowf in surface contact. The ends of leaf I3 pressupon the end portions of the main leaf ID, leaf presses at its ends upon leaf I3,v the ends of leaf I5 press 4 upon leaf I4, and the ends of leaf I6 press upon leaf I5. This is what is termed in the trade as proper snap for the secondary leaves. Leaves I6, Il and i8 may be substantially unstressed in the nal assembly, or in other words, they are not provided with any snap.

It will' be evident from the foregoing. that I haveprovided a methodA for the manufacture of leaf springs which greatly reduces the number` of handling operations required. It is only necessary to handle acomplete assembly of all of the leaves, as distinguished from the prior practice of handling the leaves separately. In fact the expensev andtime' required to heat, bend and harden all' of the leaves in one general operation is no greater than that required in the past for each individual' leaf. Only one set of forms or pattern strips is required for all of the leaves, Whereas" in the past a set of forms must be provided for each individual leaf, thus involving considerableexpense for these parts as; wel# as consuming time-for their insertion ih-tlebendingi machine. Also the final assembly'i's siinplntham conventional practice, which have been preparedE in this fashion can more; readily assembled into-the flnwll spring. 'lroublesome' selection andsor-tingfof thev'leaivsiusedlfol? thentl' assemblies isi eliminated' andL because all ofithe* leaves are bent in one operation. no difficulty in' experiencedI irr` maintainingk proper alignment ot the shackleboltl eyes..

By virtue ofthe simplicity andsaving'seif'ocail by my methodi the over-ali cost/ of producing springs. in considerable quantitiesf isf greatly rel-- duced, and the: capacity' of a given' plant insteld lation cany be greatly' increased'. Spot. tests oni production can be readily made'y at frequent in tervals' as distinguished. from: the difficulty iw making. checks on production' by the prior de scribed method. Thevaricus manual operations involved are' quite' simple' andi can be' readily mastered by ordinary workmen without a long period of training..

I claim:

l. In a method for the manufacture of. vehicle springs of: the semi-ellipticalleaftype1, assembling the unhar'clenedi leaves generally' in the1 ordeif'of their length,.the secondary leaves being disposedv on that side of. the" main; leaf whichlis' tobe the: concave sidev after bending', applying.' a'. retaining member throughf thel centers4 oil the leaves to' loosely retain! the' assembled: relationship',` heatr ing: the complete' assembly; ending the complete assembly to thereby' provide the proper curvaturein one operation' for all ofthe leaves, reheatinl andV chilling. the' assembly' to: harden' the satire;V and thenA reassembling the' leaves in normallorder with the secondary leavesA on the convent side of the main leaf.

2. In a method for'the'manutactu're.' of vehiclu springs of the semi-elliptical' leaf' typeg. tlm'y steps of assembling' the unhardened'- leavesv irrther gena' eral order of their length onY that side'of the main leaf which is to be thef concave side: after' manu facture, and with the' centers-offtli'efleavesmligmw on` a Commony axis; heating. the aseemblyf bending the `assembly While hot to provide in one bending operation the proper cuifvature' for' all of the leaves aridwitlfl the' socondar-y'leavesbeingf bent to curvatures greater than that' of the mam leaf, hardening the bent leaves, and assembling the leaves with the secondaryleavesonI the'coll- Vex side of the lnainleaf.

3. In a method for' th'e manufacture of vehicle springs of the' semi-elliptical leaf type,- thel steps' of loosely assembling the unhardened leaves in the general order of their length on that side of the main leaf which is to be the concave side after manufacture and with the centers of the leaves aligned on a common axis, heating the assembly, bending the assembly While hot to provide in one bending operation the proper curvatures for all of the leaves and with the secondary leaves being bent to final curvatures greater than that of the main leaf, hardening the bent leaves while so assembled, and then reassembling the leaves with the secondary leaves on the convex side of the main leaf.

4. In a method for the manufacture of vehicle springs of the semi-elliptical leaf type, the steps of assembling the unhardened leaves in the general order of their length on that side of the main leaf which is to be the concave side after manufacture, and with the centers of the leaves aligned l on a common axis, applying retaining means to the leaves to loosely retain the assembled relationship, heating the assembly, bending the assembly while hot to provide in one bending operation the proper final curvature for all of the leaves, and with the secondary leaves being bent to ourvatures greater than that of the main leaf, hardening the bent leaves while so assembled, and then reassembling the leaves with the secondary leaves on the convex side of the main leaf.

HARRY B, CLARY.

REFERENCES CITED UNITED STATES PATENTS Name Date Number Williams Aug. 14, 1932 

